title: Comparison of the electrophysiological pattern of fatigue between athletes required to perform explosive and endurance sports.
abstract: The electrophysiological behavior of an isometric contraction sustained to fatigue, was examined in 6 long distance runners and 9 athletes involved in explosive (burst) sports, by on line computer analysis of the electrical activity of vastus medialis, rectus femoris and vastus lateralis. The experiments were carried out with a counterload of 50% of the maximal strength of the muscle. The duration of spike increased and the frequency decreased in the 3 examined muscles, in both types of sport. In the burst sports the changes of value of both parameters were statistically significant in the 3 muscles. In endurance sports the variations of duration were not significant and the changes of frequency were statistically significant only in the vastus lateralis. These results could be explained by the gradual activation of motor units of more strikingly different sizes in burst sports. Thus it may be speculated that prolonged training in burst sports may result in the automatic mobilization of higher number of small motor units, for the initiation of contraction while in endurance sports the onset of contraction is more gradual and carried out by large motor units.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Hadassah University Hospital, Jerusalem, Israel.
authors.forename: J J
authors.initials: JJ
authors.lastname: Vatine
authors.forename: A
authors.initials: A
authors.lastname: Blank
authors.forename: M
authors.initials: M
authors.lastname: Shochina
authors.forename: A
authors.initials: A
authors.lastname: Swissa
authors.forename: Y
authors.initials: Y
authors.lastname: Mahler
authors.forename: B
authors.initials: B
authors.lastname: Gonen
authors.forename: A
authors.initials: A
authors.lastname: Magora
mesh_terms: D000293:Adolescent; D000328:Adult; D004594:Electrophysiology; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D013177:Sports